Showing 6 results for Ghorbani Shahna
I Mohammadfam, H Mohamadi, F Ghorbani Shahna, A R Soltanian,
Volume 3, Issue 1 (5-2013)
Abstract
Introduction: In HSE management systems competency has been considered as an important tool for selecting managers and resource allocation. Lack of proper HSE managers can undermine the performance of the management system. On the other hand competent HSE managers can improve the performance of management system and reduce the time to perform activities. This study was aimed to present a model to select the HSE managers.
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Material and Method: In this study, similar models were examined to select the basic framework. Model dimensions and weights were determined using the focus group technique. The model was used in a large industrial company. The model was approved by the evaluation of the results and correction of the identified defects.
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Result: The approved model included technical, behavior and concept competence. Technical competence for managers in level 1 and 2 and behavior competence for managers in level 3, were the most important dimensions.
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Conclusion: HSE managers in various level should have different competencies which can be evaluated by presented model in the current study, before employment and also it can be used as a basis for monitoring individuals during specific period of time.
Mahdi Jamshidi Rastani, Farshid Ghorbani Shahna, Abdolrahman Bahrami, Somayeh Hosseini,
Volume 6, Issue 2 (6-2016)
Abstract
Introduction: Adherence to the design values and ventilation standards (VS) after installing and also maintaining continuous work of ventilation system with maximum performance throughout its life are amongst the reasons of ventilation systems monitoring. Therefore, the aim of this study was to evaluate performance of local exhaust ventilation system for control of dust by measuring the operating parameters and also to compare it with ventilation standards (VS) and design values.
Material and Method: The present research is a descriptive and cross-sectional study, conducted in three sections of measuring, monitoring and evaluating the operating parameters on hoods, channels and fan of ventilation system based on the current status of the system, documentation (design), and recommended standards (VS). Static pressure, velocity pressure, surface area, and flow rate were measured based on the recommendations of various sources and ACGIH industrial ventilation manual, and the data were compared with the design and recommended values, using the SPSS software version 16.
Result: The results of paired sample t-test between flow rate and velocities of design and current status, showed significant differences in various parts. Accordingly, the results revealed a reduction of more than 50% in the design duct velocity compared to the current duct velocity, while design duct velocity is 1.3 more than the standard duct velocity of current status, and current duct velocity is about 65% of standard duct velocity.
Conclusion: The reduction and nonconformity of the results of measurements of operating parameters (after a minimum of two decades) with design and standard values are corroborant and sufficient reason for obstructions, abrasions, leaks, imbalance of system ducts and their inefficiency in some branches. Since there is no base line measurements for system (supposing that the system worked with maximum amounts of setup time), one of the reasons for these changes can be attributed to lack of schedule for regular and appropriate maintenance.
Mahdi Jamshidi-Rastani, Farshid Ghorbani Shahna, Abdolrahman Bahrami, Somayeh Hosseini, Abdullah Barkhordari,
Volume 7, Issue 4 (12-2017)
Abstract
Introduction: Efficiency of hoods for local exhaust ventilation system is influenced by hood geometry, its situation relative to the process and the air volume exhausted by it. The aim of this study was to present a simple and practical method based on the standards for assessment of potential problems of ventilation system in a steel making company.
Material and Method: In this cross-sectional study, a checklist based on the ACGIH ventilation standards was developed for investigating potential problems related to the three types of hoods in an oxide screen process. This checklist has completed in order to feasibility study of corrective changes in evaluation of the hood hardware parameters. The differences between design and current status to the standards were considered as noncompliance. Finally, differences were analyzed statistically.
Result: Based on statistical analysis, the average of current status of hoods, plans and design documents and standards were for variables of conveyors downstream enclosure (1.6, 2.38 and 2.41m), vertical distance from hoods to conveyors (0.39, 0.37 and 0.61m), conveyor longitudinal enclosing after hood (1.225, 1.288 and 0.296 m) and hood numbers (18, 17 and 31), respectively. Comparing the results between current status of hoods with plans and design documents showed no significant differences (0. P-value≤ 0.05). But, the results between current status of hoods and design documents with standards have significant difference (0. P-value≥ 0.05). A significant difference (0. P-value≥ 0.05) revealed between the average of the current status of hoods, plans and design documents and the standards for variables of hood flow (813.3, 2276.9 & 3085.9 cfm) and duct velocity leading to the hoods (2289.3, 5083.5 & 3500 fpm), respectively.
Conclusion: This method can be applicable for the local ventilation systems with extensive pollution sources and hoods. One of the advantages of this method can be easily application of this system, as one of the requirements for delivering ventilation systems from contractors and the use of it for studying potential problems of the hoods that they have standards. Also, by comparing current status of hoods with the design specifications and standards, the mismatches/ unconformities in the lifetime and maintenance process of the system can be understood.
Shiva Soury, Abdulrahman Bahrami, Saber Alizadeh, Farshid Ghorbani Shahna, Davood Nematollahi,
Volume 10, Issue 2 (5-2020)
Abstract
Introduction: In this study, Zn3(Btc)2 (metal organic framework) sorbent was introduced for sampling of Benzo[a]pyren from the air. The purpose of this study was to develop the sampling and analysis method by needle trap, with no sample preparation step.
Material and method: Zn3(Btc)2 sorbent was electrochemically synthesized and its properties were specified by FTIR, FE-SEM, and PXRD techniques. A glass chamber with a temperature of 120°C was used to make the certain concentration of Benzo[a]pyren. Factors affecting the efficiency of needle trap were evaluated and optimized using a response surface method considering a specific operating interval to achieve the highest efficiency. The performance of the proposed method was also investigated using the real samples.
Results: The highest desorption efficiency of Benzo[a]pyren was obtained when using the needle trap containing Zn3 (Btc)2 sorbent at 379°C and 9 min retention time. No significant reduction was observed in the analyte concentration by maintaining the sampler for 60 days. The limit of detection and limit of quantification of Benzo[a]pyren were obtained 0.01 and 0.03 mg/m3, respectively. The percentage of standard deviation of the measured values of Benzo[a]pyren in diesel exhaust was calculated 4.1%.
Conclusion: The highest desorption efficiency of Benzo[a]pyren was obtained when using the needle trap containing Zn3 (Btc)2 sorbent at 379°C and 9 min retention time. No significant reduction was observed in the analyte concentration by maintaining the sampler for 60 days. The limit of detection and limit of quantification of Benzo[a]pyren were obtained 0.01 and 0.03 mg/m3, respectively. The percentage of standard deviation of the measured values of Benzo[a]pyren in diesel exhaust was calculated 4.1%.
Adel Jafari, Farshid Ghorbani Shahna, Abdulrahman Bahrami, Majid Habibi Mohraz,
Volume 13, Issue 2 (6-2023)
Abstract
Introduction: With the spread of the COVID-19 pandemic and the lack of adequate protection by existing protective equipment, many researchers’ attention has turned to developing improved respiratory protection equipment. Considering their special properties and nanoscale dimensions, electrospun nanofibers are a suitable option for improving operational characteristics of substrates used in conventional facemasks. This study aimed to optimize the electrospinning process of polyacrylonitrile nanofibers (PAN) containing ZIF8 and use the optimized substrate in medical facemasks to increase their protective performance.
Material and Methods: This study employed an environmentally friendly method to synthesize ZIF8 in an aqueous environment. Then, PAN/ZIF8 polymer solutions were prepared in dimethylformamide. The effects of electrospinning parameters, including electrospinning voltage, polymer solution concentration, electrospinning distance, and polymer injection flow rate on diameter and uniformity of nanofibers were investigated. Electrospinning conditions were optimized using response surface methodology (RSM) and central composite design (CCD) to obtain desired values for response (dependent) variables. Finally, optimized PAN/ZIF8 and PAN nanofibers were electrospun on spun-bond substrate. Base weight, average diameter of fibers, filtration performance, pressure drop, and quality factor of fabricated substrates were assessed.
Results: According to results, optimal conditions for electrospinning of PAN/ZIF8 polymeric solution for polymer concentration (A), electrospinning voltage (B), electrospinning distance (C), and polymer injection flow rate (D) were respectively 70 w/v%, 20 kV, 18 cm, and 0.4 ml/h. Moreover, despite lower base weight of PAN/ZIF8 nanofiber mask, it displayed higher filtration performance (98.51%), lower pressure drop (31.42 Pa), and higher quality factor (0.140 Pa-1) in comparison to other studied masks.
Conclusion: Experimental models developed in this study provide acceptable values for filtration efficiency and quality factor for filtration applications. Additionally, they serve as a guideline for subsequent experiments to produce uniform and continuous nanofibers with desired diameter for future applications in absorbent media (intermediate absorbent layers) of respirators.
Nematullah Kurd, Abdulrahman Bahrami, Abbas Afkhami, Farshid Ghorbani Shahna, Mohammad Javad Assari, Maryam Farhadian,
Volume 13, Issue 3 (9-2023)
Abstract
Introduction: Toluene, benzene, xylene, and ethylbenzene (BTEX) belong to the class of monocyclic aromatic hydrocarbons and are identified as toxic volatile compounds due to their harmful properties. The reliable biomarkers for occupational exposure to these toxic compounds are hippuric acid (HA), trans,trans-muconic acid (tt-MA), mandelic acid (MA), and methylhippuric acid (MHA), which correlate with toluene, benzene, ethylbenzene, and xylene, respectively.
Material and Methods: A novel magnetized imine-linked covalent organic framework (Fe3O4@TFPA-Bd) was synthesized, marking its inaugural use as a sorbent in microextraction by packed sorbent (MEPS). The synthesis of Fe3O4@TFPA-Bd was executed in a straightforward and efficient manner, using Fe3O4 nanoparticles as the magnetic core and benzidine (Bd) and Tris (4-formyl phenyl) amine (TFPA) as the structural building blocks. This newly produced sorbent was tested for the microextraction of hippuric acid (HA), mandelic acid (MA), trans, trans-muconic acid (tt-MA), and m-methyl hippuric acid (m-MHA) from urine samples, which were then analyzed using high-performance liquid chromatography (HPLC). In order to optimize the extraction performance, parameters like sample volume, elution volume, extraction cycles, pH, and sample solution temperature were thoroughly adjusted. The synthesized adsorbent underwent thorough characterization via scanning and transmission electron microscopy (SEM and TEM), Fourier transforms infrared spectrometer (FTIR), and X-ray diffraction (XRD).
Results: The developed method showcased promising attributes: low detection limits (0.02 µg/ml for tt-MA, S/N=3), low quantification limits (0.06 µg/ml for tt-MA, S/N=10), a solid linear range (0.5-320 µg/ml for MA, R > 0.99), and commendable intra- and inter-day precision (2.4%-4.3% and 3.1%-7.8%, respectively) for volatile organic compound (VOC) biomarkers. Furthermore, the method demonstrated recoveries in the 81-87.5% range for spiked samples, indicating its practicality and effectiveness.
Conclusion: The developed procedure was suitable for the determination of BTEX biomarkers from urine samples and can be an alternative to previous methods.
